It is known to provide an air pallet for functioning as a patient mover and transferring a patient from one surface to another surface. Such an air pallet employs a number of air sacks which include holes in the lower surfaces for expelling pressurized air contained in the air sacks. Such an air pallet develops an air film between the pallet and an underlying pallet supporting surface. The resulting air film creates a low friction air bearing between the air pallet and supporting surface or otherwise a "lift" effect. One such air pallet is disclosed in Weedling et al. U.S. Pat. No. 5,067,189.
A criticism of current air pallets is that the air which escapes the holes in the lower surfaces of the longitudinal air sacks is not exploited in the most efficient manner. More particularly, current air pallets employ longitudinal air sacks which are arranged in side-by-side relation. The air sacks have lower surfaces which contain "high air loss" holes. When inflated, the lower surfaces of the air sacks become convex, with the air sacks being supported on the supporting surface at the apex of the curvature of the convex air sacks. Consequently, tunnels or spaces form between adjacent ones of the longitudinal air sacks, which spaces or tunnels are open to atmosphere at opposite ends of the air pallet. Thus, air which escapes from the high air loss holes in the longitudinal air sacks, and which could be utilized to generate the "lift" effect, finds its way to these air tunnels or passages and rushes towards one end or the other of the air pallet, escaping to atmosphere at the ends of the air pallet.
It has therefore been one objective of the present invention to provide an air pallet which more efficiently utilizes the air escaping from the sacks of an air pallet in creating the "lift" effect or air bearing.
It is also known to provide a so-called "low air loss" mattress for supporting a patient and ventilating the skin of a patient to prevent the formation of bed sores upon the patient's skin, or otherwise to prevent the degeneration of a patient's skin during long periods of confinement to a hospital bed. Such low air loss mattresses include a number of air sacks which include low air loss holes on their upper surfaces and which allow pressurized air from within the air sacks to escape upwardly and to ventilate a patient's skin thereby. One such low air loss mattress is disclosed in Chamberland U.S. Pat. No. 4,896,389 assigned to a related company, SSI Medical Services, Inc., of the assignee of the present invention.
It is also known to provide a patient mover which includes an upper patient supporting bladder in combination with a lower high air loss air pallet. Such is shown in Blanchard et al. U.S. Pat. No. 5,065,464, also assigned to the above related company of the assignee of the present invention.
There has therefore been a need to provide a more efficient air pallet for transferring a patient from one surface to another surface as well as to provide a patient supporting mattress which provides the attributes of a low air loss surface with the functional capabilities of an air pallet and which may be used as a relatively rigid support for, for example, suspending a patient from a patient weigh scale in order to take the patient's weight.